Pixel Detectors

Pixel detectors for precise particle tracking in high energy physics have been developed to a level of maturity during the past decade. Three of the LHC detectors will use vertex detectors close to the interaction point based on the hybrid pixel technology which can be considered the state of the art in this field of instrumentation. A development period of almost 10 years has resulted in pixel detector modules which can stand the extreme rate and timing requirements as well as the very harsh radiation environment at the LHC without severe compromises in performance. From these developments a number of different applications have spun off, most notably for biomedical imaging. Beyond hybrid pixels, a number of monolithic or semi-monolithic developments, which do not require complicated hybridization but come as single sensor/IC entities, have appeared and are currently developed to greater maturity. Most advanced in terms of maturity are so called CMOS active pixels and DEPFET pixels. The present state in the construction of the hybrid pixel detectors for the LHC experiments together with some hybrid pixel detector spin-off is reviewed. In addition, new developments in monolithic or semi-monolithic pixel devices are summarized.Comment: 14 pages, 38 drawings/photographs in 21 figure

Trends in Pixel Detectors: Tracking and Imaging

For large scale applications, hybrid pixel detectors, in which sensor and read-out IC are separate entities, constitute the state of the art in pixel detector technology to date. They have been developed and start to be used as tracking detectors and also imaging devices in radiography, autoradiography, protein crystallography and in X-ray astronomy. A number of trends and possibilities for future applications in these fields with improved performance, less material, high read-out speed, large radiation tolerance, and potential off-the-shelf availability have appeared and are momentarily matured. Among them are monolithic or semi-monolithic approaches which do not require complicated hybridization but come as single sensor/IC entities. Most of these are presently still in the development phase waiting to be used as detectors in experiments. The present state in pixel detector development including hybrid and (semi-)monolithic pixel techniques and their suitability for particle detection and for imaging, is reviewed.Comment: 10 pages, 15 figures, Invited Review given at IEEE2003, Portland, Oct, 200

A review of advances in pixel detectors for experiments with high rate and radiation

The Large Hadron Collider (LHC) experiments ATLAS and CMS have established hybrid pixel detectors as the instrument of choice for particle tracking and vertexing in high rate and radiation environments, as they operate close to the LHC interaction points. With the High Luminosity-LHC upgrade now in sight, for which the tracking detectors will be completely replaced, new generations of pixel detectors are being devised. They have to address enormous challenges in terms of data throughput and radiation levels, ionizing and non-ionizing, that harm the sensing and readout parts of pixel detectors alike. Advances in microelectronics and microprocessing technologies now enable large scale detector designs with unprecedented performance in measurement precision (space and time), radiation hard sensors and readout chips, hybridization techniques, lightweight supports, and fully monolithic approaches to meet these challenges. This paper reviews the world-wide effort on these developments.Comment: 84 pages with 46 figures. Review article.For submission to Rep. Prog. Phy

PIXEL 2010 - a Resume

The Pixel 2010 conference focused on semiconductor pixel detectors for particle tracking/vertexing as well as for imaging, in particular for synchrotron light sources and XFELs. The big LHC hybrid pixel detectors have impressively started showing their capabilities. X-ray imaging detectors, also using the hybrid pixel technology, have greatly advanced the experimental possibilities for diiffraction experiments. Monolithic or semi-monolithic devices like CMOS active pixels and DEPFET pixels have now reached a state such that complete vertex detectors for RHIC and superKEKB are being built with these technologies. Finally, new advances towards fully monolithic active pixel detectors, featuring full CMOS electronics merged with efficient signal charge collection, exploiting standard CMOS technologies, SOI and/or 3D integration, show the path for the future. This r\'esum\'e attempts to extract the main statements of the results and developments presented at this conference.Comment: 8 pages, 19 figures, conference summar

Design and Prototype Performance of the ATLAS Pixel Detector

The ATLAS experiment at the LHC will have three barrel and two times five disk layers of silicon pixel detectors as the innermost elements of the Inner Tracking Detector. the detctor is built adopting the hybrid pixel technology in which 16 highly permormant FE chips are connected to a silicon sensor by means of the bump and flip-chip technique. Owing to the high bunch crossing rate of 40 MHz at the LHC and the high particle fluences a sophisticated design concept is employed. The projet is presently entering the pre-production phase. The various aspects of the detector, the expected performance and the so far obtained prototype results are presented

A method for precise charge reconstruction with pixel detectors using binary hit information

A method is presented to precisely reconstruct charge spectra with pixel detectors using binary hit information of individual pixels. The method is independent of the charge information provided by the readout circuitry and has a resolution mainly limited by the electronic noise. It relies on the ability to change the detection threshold in small steps while counting hits from a particle source. The errors are addressed and the performance of the method is shown based on measurements with the ATLAS pixel chip FE-I4 bump bonded to a 230 {\mu}m 3D-silicon sensor. Charge spectra from radioactive sources and from electron beams are presented serving as examples. It is demonstrated that a charge resolution ({\sigma}<200 e) close to the electronic noise of the ATLAS FE-I4 pixel chip can be achieved

Status of a DEPFET pixel system for the ILC vertex detector

We have developed a prototype system for the ILC vertex detector based on DEPFET pixels. The system operates a 128x64 matrix (with ~35x25 square micron large pixels) and uses two dedicated microchips, the SWITCHER II chip for matrix steering and the CURO II chip for readout. The system development has been driven by the final ILC requirements which above all demand a detector thinned to 50 micron and a row wise read out with line rates of 20MHz and more. The targeted noise performance for the DEPFET technology is in the range of ENC=100 e-. The functionality of the system has been demonstrated using different radioactive sources in an energy range from 6 to 40keV. In recent test beam experiments using 6GeV electrons, a signal-to-noise ratio of S/N~120 has been achieved with present sensors being 450 micron thick. For improved DEPFET systems using 50 micron thin sensors in future, a signal-to-noise of 40 is expected.Comment: Invited poster at the International Symposium on the Development of Detectors for Particle, AstroParticle and Synchrotron Radiation Experiments, Stanford CA (SNIC06) 6 pages, 12 eps figure